Many were surprised to learn that "Glee" heartthrob Cory Monteith turned 30 last week. And Harry Shum Jr., who plays his McKinley High classmate, hit the same milestone just last month. In fact, co-star Matthew Morrison is also close in age to both, at 33, but he plays a teacher, not a student.
But of course, casting actors who left adolescence behind long ago as high schoolers is nothing new. We officially felt old when we read that "Beverly Hills, 90210" star Gabrielle Carteris turned 50 last year. (It seems like just yesterday that she was nerdy newspaper editor Andrea Zuckerman, whose crush on Brandon Walsh inspired some cringeworthy moments). And Carteris, who took on the role at 29 and was 32 by the time the West Beverly gang graduated, had mature company among some of her 20-something cast mates.
What other actors pushing 30 have played teens? We present 25 of our favorite 25-and-up stars who've gone back to high school on screen.